A sturdy table beneath the bulletin board is strewn with heavy stacks of blueprints detailing one of the most ambitious ice palace projects ever attempted.

Precise lines depicting projectile-shaped towers, flying buttresses, massive walls and intriguing grottoes fill pages of plans. One tower, according to the blueprint, will soar 150 feet above Lake Phalen, a recreational body of water in sprawling Phalen Park on the city`s north side. If it were to survive the occasional thaws that have plagued the enterprise since workers set the first block of ice into place on Jan. 6, that ice tower supposedly would distinguish the palace as the tallest of its kind man has ever built. The record so far, experts say, is held by the ice palace constructed for the 1888 St. Paul Winter Carnival, the tower of which attained 140 feet.

Sharing space with the building permit on the bulletin board is a photograph of St. Paul`s very first ice palace, the showpiece of the inaugural Winter Carnival held 100 years ago.

The picture depicts a grim, medieval fortress with a central tower 106 feet high and an edifice 180 feet long. A caption says, ``This structure launched Saint Paul into the international limelight for civic celebrations throughout the world.``

In January of 1985, a full year before the 100th anniversary of that launching, leaders of the St. Paul Winter Carnival approached Charlie Hall, a veteran carnival booster and retired owner of the Mermaid Supper Club and Bowling Center. They asked Hall to find out if an ice palace exceeding even the 1888 model in size could be built in modern times. Hall, who knows a lot of construction people, learned the feat would be possible, and he exulted.

``I was brought up just a mile-and-a-half from where an ice palace was built in 1941,`` Hall said during a pause in his promotional and coordinating efforts a few days ago. ``Now, that was a spectacular sight to behold.``

Hall is one of many old-timers around St. Paul who act as living repositories for memories of carnivals past. ``I remember when big companies would dress up their employees in bright-colored uniforms made of wool,`` he said. ``All of them would march around downtown. Everybody would get into it back in those days.``

Local wage-earners, these days, may not be so willing to smother their identities in company-sponsored uniforms, but they do get into the spirit. More than 1,200 citizens have volunteered to work during the carnival period, Jan. 22 through Feb. 9, by arranging and supervising such activities as stock car races on ice, snowshoe softball games, hot air balloon flights, skating exhibitions, ice-sculpting contests and parades.

An additional 1,000 unpaid volunteers will be manning donated construction equipment to build the palace, a project that would cost an estimated $1.5 million otherwise.

To pay for some $200,000 worth of supplies and utilities that couldn`t be donated, benefactors have been snapping up $10 certificates attesting to their ``ownership`` of one 24-inch by 48-inch, 800-pound block of ice palace ice.

Hall said 35,000 such certificates will have gone on the market before the carnival ends. Scarcely more than 30,000 blocks of ice actually will be used in the structure, but some of those will be broken into smaller pieces to fill in details, so there should be plenty of authentic certificates to go around.

The frenzy of pre-Carnival civic enthusiasm, though, could best be witnessed at the construction site itself. In the shadows of four 50-ton cranes provided by the main contractor, Austin P. Keller Construction Co., volunteer members of the St. Paul building trades scurried over the monolith, which had reached 8 feet in height early this month.

Fifty workers for each of the two 8-hour shifts per day, six days a week, sign on for a nominal $1 an hour (which is then contributed to the state`s workmens` compensation pool). At least that many citizens per shift turn up at Phalen Park to watch the activity.

On cold days, those observers sit in parked cars with the engines running and marvel as the cranes lift the blocks into place with giant ice tongs while workers secure the joints with ``mortar`` made from slush.

``We`re running three to five days behind schedule,`` Tom Keller, president of the construction firm, reported after an unusually mild weekend. ``These thaws have held us back.``

Hit by another thaw this week, contractors and designers agreed to eliminate some minor features and scale down the main tower to 116 feet, settling for the title of second tallest ice palace in history.